Evaluation of Silica Uptake from Foliar-Applied Silicon Nanoparticles in Melon (Cucumis melo L.) under Soilless Culture

Abstract

Melon (Cucumis melo L.) is one of the fruit commodities which get a great interest to be developed in Indonesia and has a high nutritional value. However, the fungal infection and pathogens in melon cultivation are considered significant problems that are difficult to manage. Therefore, efforts are needed to improve the productivity and quality of melon and prevent pest and disease attacks. One mineral nutrient that is assumed to enhance plant resistance and increase the quality and production of melon is silica. The purpose of the research was to evaluate silica absorption from foliarapplied silicon nanoparticles in melon under soilless culture and improve melon fruit's growth and quality by applying silica fertilizer. This experiment was conducted in the greenhouse at IPB University, Leuwikopo experimental station (Indonesia), from February to May 2021. The experimental design used in this study was a splitplot randomized complete block design 3 x 2 factorial pattern with four replicates, i.e., by adding silica fertilizer and using two varieties of melon. The main plot factor is applying silica fertilizer (Novelgro, water-soluble), consisting of 3 silica concentrations, namely 0.67; 1.33 ppm, and control (without silica). The subplot factor is melon varieties consisting of Alisha and Glamour. Experimental data were analyzed using analysis of variance and followed by Duncan's Multiple Range Test (DMRT) if there is a significant effect. The findings showed that the foliar application of silica fertilizer significantly increased the plant height, stem diameter, internode length, total number of hermaphrodite flowers, number of hermaphrodite flowers that are swelling, while decreased the fruit moisture content and gave the best average fruit position. Instead, melon cultivars produced in soilless culture differed substantially in terms of growth rate and fruit quality. Glamour cultivars' growth rate and fruit quality increased significantly regarding plant height, stem diameter, internode length, leaf area, fruit weight, fruit diameter, fruit length, total soluble solids, flesh thickness, and rind thickness, while decreased number of fallen hermaphrodite flowers. In contrast, the Alisha cultivar gave a better growth rate regarding the number of leaves, the total number of hermaphrodite flowers, and the number of swollen hermaphrodite flowers. However, the results of this study did not show any interaction between treatments on the experimental parameters. Moreover, our study indicated that the melon plant could absorb silica in the low category (<1% Si). The highest silica contents were found in the Alisha cultivar leaves and the Glamour cultivar's rinds treated with the silica concentration of 1.33 ppm as much as 0.34% and 0.30%, respectively.